What If?

The UK and US No. 1 bestseller.

Serious Scientific Answers to Absurd Hypothetical Questions. From the creator of the wildly popular xkcd.com, hilarious and informative answers to important questions you probably never thought to ask.

Millions visit xkcd.com each week to read Randall Munroe's iconic webcomic. Fans ask him a lot of strange questions: How fast can you hit a speed bump, driving, and live? When (if ever) did the sun go down on the British Empire? When will Facebook contain more profiles of dead people than living? How many humans would a T Rex rampaging through New York need to eat a day?

In pursuit of answers, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations and consults nuclear reactor operators. His responses are masterpieces of clarity and hilarity, complemented by comics. They often predict the complete annihilation of humankind, or at least a really big explosion.

"Nerd Royalty."
Ben Goldacre

"Brilliant."
Rolling Stone

Preface to the UK Edition
Disclaimer
Introduction
Global Windstorm
Relavistic Baseball
Spent Fuel Pool
Weird (and Worrying) Questions from the What if? Inbox, #1

• New York-Style Time Machine
• Soul Mates
• Laser Pointer
• Periodic Well of the Elements
• Everybody Jump
• A Mole of Moles
• Hair Dryer

Weird (and Worrying) Questions from the What if? Inbox, #2

• The Last Human Light
• Machine-Gun Jetpack
• Rising Steadily

Weird (and Worrying) Questions from the What if? Inbox, #3

• Orbital Submarine
• Short-Answer Section
• Lightning

Weird (and Worrying) Questions from the What if? Inbox, #4

• Human Computer
• Little Planet
• Steak Drop
• Hockey Puck
• Common Cold
• Glass Half Empty

Weird (and Worrying) Questions from the What if? Inbox, #5

• Alien Astronomers
• No More DNA
• Interplanetary Cessna

Weird (and Worrying) Questions from the What if? Inbox, #6

• Yoda
• Flyover States
• Falling with Helium
• Everybody Out

Weird (and Worrying) Questions from the What if? Inbox, #7

• Self-Fertilization
• High Throw
• Lethal Neutrinos

Weird (and Worrying) Questions from the What if? Inbox, #8

• Speed Bump
• Lost Immortals
• Orbital Speed
• FedEx Bandwidth
• Free Fall

Weird (and Worrying) Questions from the What if? Inbox, #9

• Sparta
• Drain the Oceans
• Drain the Oceans: Part 2
• Twitter
• Lego Bridge
• Longest Sunset
• Random Sneeze Call

Weird (and Worrying) Questions from the What if? Inbox, #10

• Expanding Earth
• Weightless Arrow
• Sunless Earth
• Updating a Printed Wikipedia
• Facebook of the Dead
• Sunset on the British Empire
• Stirring Tea
• All the Lightning
• Loneliest Human

Weird (and Worrying) Questions from the What if? Inbox, #11

• Raindrop
• SAT Guessing
• Neutron Bullet

Weird (and Worrying) Questions from the What if? Inbox, #12

• Richter 15
• Acknowledgments
• References